Objective: This study examined the relationship between cooking frequency and frequency of intake of a Japanese well-balanced diet among those living alone and to explore whether cooking frequency is good for Japanese well-balanced diet.

Methods: We used data from 1,076 people living alone which were obtained from an online survey, conducted in November 2020, on 6,000 men and women aged 20~64 from around the country. The demographics, the frequency of intake of a Japanese well-balanced diet, number of vegetable dishes per day, and the frequency of meals prepared away from home (e.g., eating at restaurant, ready-made meals) were compared by five groups according to cooking frequency using χ² test. Then, we examined the relationship between cooking frequency and the frequency of intake of a Japanese well-balanced diet using logistic regression analysis.

Results: A total of 1,074 people (647 males and 427 females) were analyzed, excluding two people whose weight responses were incomplete. The group that cooked every day had significantly higher frequency of daily intake of a Japanese well-balanced diet than the group that cooked rarely, even after adjustment for the demographics and frequency of meals prepared away from home [odds ratio 2.55 (95% confidence interval (1.63~3.98)].

Conclusion: Among those living alone who cooked every day had higher frequency of intake of a Japanese well-balanced diet. To explore cooking frequency for a Japanese well-balanced diet, it is necessary to examine the characteristics of those who consume a Japanese well-balanced diet even if their cooking frequency is not daily.

Objective: The present study aimed to explore the effects of habit of dinner before bedtime (HDB) on sleep disorder among Japanese university students.

Methods: From November to December 2016, 360 1st~2nd grade students at one university in Hokkaido prefecture, Japan, participated in this study. Sleep disorder was assessed using the Japanese version of the Pittsburgh Sleep Quality Index (PSQI-J), which defines a score of ≥6 as indicating the presence of sleep disorder. HDB was defined as eating dinner 2 hours or less before bedtime 3 times or more per week. A second survey was conducted 1 year later, from November to December 2017. We analyzed changes in the PSQI-J score after 1 year between participants with HDB and those without HDB using analysis of covariance (ANCOVA). Moreover, we identified participants without sleep disorder at the baseline survey, and the association between HDB at baseline and onset of sleep disorder was examined using Poisson regression analysis.

Results: The ANCOVA was conducted on 256 participants, and revealed significantly higher PSQI-J scores among the group with HDB compared to the group without HDB after 1 year. The Poisson regression analysis was conducted on 109 participants, and revealed significantly higher incidence of sleep disorder among the group with HDB (risk ratios: 1.97, 95% confidence interval: 1.09~3.77), compared to the group without HDB.

Conclusion: The present study clarified university students with HDB have higher risk of developing sleep disorder. Our results may be useful for improving the quality of sleep among young adults.

Objective: Ordering the appropriate amount of food at restaurants can contribute to both food waste reduction and health promotion. This study investigated the characteristics of people who order the appropriate amount of food at restaurants.

Methods: The study conducted a survey of 1,000 men and women aged 20 to 64 years who registered with an internet research company. Data were collected in September 2021. The respondents were asked how often they ordered a meal for one person at a restaurant for each of four items, using a four-point scale from never (1) to often (4). After the total frequency score was obtained, the respondents were divided into three groups: low-, medium-, and high-scoring groups. The groups were compared using the Kruskal–Wallis test for body mass index (BMI) and χ² test for other items.

Results: The distribution of the three groups was 317 (31.7%) in the low-scoring group, 322 (32.2%) in the medium-scoring group, and 361 (36.1%) in the high-scoring group, respectively. Those who ordered the appropriate amount were more likely to be female and more highly educated (p = 0.009, p = 0.001, respectively) and less likely to have a low income (p = 0.047). They also had a healthy diet (p < 0.001), a higher subjective sense of health (p = 0.014), and a lower BMI (p = 0.009).

Conclusions: For promoting the behavior of ordering the appropriate amount of food, health authorities should formulate an approach targeting males, those with lower education or lower income, and environmental improvement in restaurants.

Objective: This study conducted a nutritional evaluation of the boxed lunches sold at supermarkets in Akita Prefecture based on the six-item criteria of "healthy meals (smart meals)."

Methods: Bento meals were evaluated according to the ingredients, and nutritional calculation was performed. Accordingly, the smart meals were divided into two categories: those with less than 650 kcal and those with more than 650 kcal of total energy intake. A statistical analysis was performed to compare the fish lunches (n = 11) and meat lunches (n = 14) using six nutritional characteristics and reference values.

Results: Ten (40%) of the 25 boxed lunches examined had less than 650 kcal, while ten (40%) had more than 650 kcal of total energy intake; the remaining five (20%) had an energy intake of more than the upper limit of 850 kcal. There were no boxed lunches that met all the six criteria, and only 11 (44%) fulfilled four or five criteria. Notably, 44% of the boxed lunches fulfilled the required protein/fat/carbohydrate energy% (PFC%E), 40% of boxed lunches had an excessive amount of salt equivalent, and all of them lacked adequate vegetable contents. There was no significant difference in the energy contents between the meat and fish lunches (p = 0.071).

Conclusions: It was found that all boxed lunches had insufficient vegetable content, almost half had inadequate PFC%E, and 40% had excess salt equivalent. Thus, most lunch boxes have nutritional balance issues.

Objective: We aimed to reveal the nutritional issues of Guatemalan school children (SC) by comparing anthropometric data and school lunch (SL) history in Guatemala with those in Japan and discuss the role of SL in improving Guatemalan SC's nutritional status.

Methods: We compared the height and weight data collected in 2017 of 3,282 Guatemalan SC living in S city and Japanese SC based on school-health statistics. Information regarding SL history and lunch menus in both countries was collected through a literature review and field research in Guatemala. Nutrient values of SLs were calculated by estimating the kind and weight of ingredients using photographs.

Results and Discussion: The mean values of height and weight of Guatemalan SC (6~12 years) were lower than those of Japanese SC in 2017. Interestingly, the height (in 2017) of the Guatemalan SC was like that of the Japanese SC (in 1948), when the Japanese were facing severe malnutrition. Although Japanese SL has been served as lunch without fail until now, Guatemalan SL has been served as snacks intermittently. In Japan, the concept of SL was initiated in 1947, and the School Lunch Act was enacted seven years later; while it took 58 years in Guatemala.

Conclusion: Although 60 years have passed since SL began, Guatemalan SC have not only experienced malnutrition but stunted growth. In Japan, SL is contributing to improving nutritional conditions and constitution among SC. The continuous provision of nutritious SL in accordance with the Law may be necessary to improve the nutritional and anthropometric status of Guatemalan SC.

Objective: This study examined the relationship between the Skin Carotenoid (SC) score and the number of vegetables dishes consumed to use the former in nutrition education in Japan.

Methods: From June to November 2020, 551 people from 19 facilities in Japan conducted SC score measurement and questionnaire surveys. SC score was compared by attribute and food intake status using t-test and one-way analysis of variance. The relationship between the SC score and the number of vegetables dishes was examined by simple regression analysis.

Results: This study included 520 subjects (analytic rate 94.4%). The average SC score (standard deviation) was 377 (109). The SC score was higher among those who consumed more vegetable dishes, females, people in their 60s or older, non-smokers, and those who consumed fruit, vegetable juice, green juice, and supplements. As a result of simple regression analysis, the SC score increased as the number of vegetable dishes consumed increased (p < 0.001). The regression equation was "SC score = 22.6 × the average number of vegetable dishes consumed + 324." Despite adjusting for attributes and non-vegetable food intake, the number of vegetable dishes affected the SC score (p < 0.001).

Conclusion: The higher the SC score indicates that more vegetables were eaten. This suggests that SC score can be used as an indicator of vegetable intake. The regression equation allows the number of vegetable dishes using the SC score to be estimated. It is expected that SC score can be used in nutrition education in the future.